TRIPROLIDINE AND PSEUDOEPHEDRINE
Clinical safety rating: safe
CNS depressants may enhance sedative effects May cause marked drowsiness and impair mental and physical abilities.
Triprolidine is a first-generation antihistamine that antagonizes histamine H1 receptors, reducing histamine-mediated allergic symptoms. Pseudoephedrine is a sympathomimetic amine that acts as a decongestant by stimulating alpha-adrenergic receptors in the respiratory tract mucosa, causing vasoconstriction and decreased nasal congestion.
| Metabolism | Triprolidine is metabolized via hepatic hydroxylation and conjugation. Pseudoephedrine is partially metabolized in the liver by N-demethylation to inactive metabolites; the remainder is excreted unchanged in urine. |
| Excretion | Triprolidine: renal, 70% unchanged and metabolites. Pseudoephedrine: renal, 90% unchanged. |
| Half-life | Triprolidine: 2-4 hours (parent compound). Pseudoephedrine: 4-8 hours, prolonged in alkaline urine (up to 16-24 hours). |
| Protein binding | Triprolidine: ~90% bound to plasma proteins. Pseudoephedrine: <10% bound. |
| Volume of Distribution | Triprolidine: ~2.5-3.5 L/kg. Pseudoephedrine: ~2.5-3.5 L/kg. |
| Bioavailability | Oral: Triprolidine ~70-80%; Pseudoephedrine ~80-90% (immediate-release). |
| Onset of Action | Oral: Triprolidine ~30 minutes; Pseudoephedrine ~30-60 minutes. |
| Duration of Action | Immediate-release: 4-6 hours for both components. Extended-release formulations provide 12-hour duration. |
1 tablet (2.5 mg triprolidine/60 mg pseudoephedrine) orally every 4-6 hours; max 4 tablets/24 hours.
| Dosage form | TABLET |
| Renal impairment | eGFR 30-59 mL/min: Administer every 8-12 hours; eGFR <30 mL/min: Not recommended due to accumulation risk. |
| Liver impairment | Child-Pugh A: No adjustment; Child-Pugh B or C: Contraindicated due to risk of CNS depression. |
| Pediatric use | Children 6-12 years: 0.5 tablet (1.25 mg/30 mg) orally every 4-6 hours; max 2 tablets/24 hours. Children <6 years: Not recommended. |
| Geriatric use | Start at lowest dose; consider alternative due to increased risk of anticholinergic effects, dizziness, and hypertension. Max 2 tablets/24 hours. |
| 1st trimester | Consult provider |
| 2nd trimester | Consult provider |
| 3rd trimester | Consult provider |
Clinical note
CNS depressants may enhance sedative effects May cause marked drowsiness and impair mental and physical abilities.
| FDA category | Animal |
| Breastfeeding | Pseudoephedrine is excreted into breast milk (M/P ratio approximately 3.5). It may reduce milk production via prolactin suppression. Triprolidine is excreted in small amounts; risk of sedation and irritability in the infant. Consider non-sedating antihistamines and decongestants when possible; caution advised. |
| Teratogenic Risk |
■ FDA Black Box Warning
None.
| Common Effects | Sedation |
| Serious Effects |
["Hypersensitivity to triprolidine, pseudoephedrine, or any component of the formulation","Severe hypertension or coronary artery disease","Concurrent use or within 14 days of MAO inhibitor therapy","Narrow-angle glaucoma","Urinary retention","Severe renal impairment"]
| Precautions | ["Cardiovascular effects: Use with caution in patients with hypertension, ischemic heart disease, or arrhythmias.","CNS depression: May cause drowsiness; avoid activities requiring mental alertness.","Anticholinergic effects: Use with caution in patients with glaucoma, prostatic hyperplasia, or urinary retention.","Drug interactions: Avoid concurrent use with MAO inhibitors or within 14 days of stopping MAO inhibitors. May interact with other sympathomimetics and antihypertensives.","Pediatric use: Caution in children less than 6 years of age due to increased risk of paradoxical reactions."] |
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| Triprolidine and pseudoephedrine are classified as FDA Pregnancy Category C. Insufficient human data exist; animal studies have shown adverse effects. First trimester: Theoretical risk of vascular disruption with pseudoephedrine; avoid if possible. Second/third trimesters: Pseudoephedrine may cause uterine artery vasoconstriction and reduced placental perfusion; avoid near term due to risk of neonatal irritability and transient hypertension. |
| Fetal Monitoring | Monitor maternal blood pressure and heart rate due to pseudoephedrine's sympathomimetic effects. Assess fetal heart rate and uterine activity if used in third trimester. Observe newborn for signs of stimulant withdrawal or irritability if used near term. |
| Fertility Effects | No well-documented effects on fertility in humans. Animal studies with pseudoephedrine suggest potential for reduced fertility at high doses. Triprolidine has no known fertility effects. |